.\"
.\"  Device driver optimized for the Symbios/LSI 53C896/53C895A/53C1010
.\"  PCI SCSI controllers.
.\"
.\"  Copyright (C) 1999-2000  Gerard Roudier <groudier@club-internet.fr>
.\"
.\"  This driver also supports the following Symbios/LSI PCI SCSI chips:
.\"	53C810A, 53C825A, 53C860, 53C875, 53C876, 53C885, 53C895,
.\"	53C810,  53C815,  53C825 and the 53C1510D is 53C8XX mode.
.\"
.\"
.\"  This driver for FreeBSD-CAM is derived from the Linux sym53c8xx driver.
.\"  Copyright (C) 1998-1999  Gerard Roudier
.\"
.\"  The sym53c8xx driver is derived from the ncr53c8xx driver that had been
.\"  a port of the FreeBSD ncr driver to Linux-1.2.13.
.\"
.\"  The original ncr driver has been written for 386bsd and FreeBSD by
.\"          Wolfgang Stanglmeier        <wolf@cologne.de>
.\"          Stefan Esser                <se@mi.Uni-Koeln.de>
.\"  Copyright (C) 1994  Wolfgang Stanglmeier
.\"
.\"  The initialization code, and part of the code that addresses
.\"  FreeBSD-CAM services is based on the aic7xxx driver for FreeBSD-CAM
.\"  written by Justin T. Gibbs.
.\"
.\"  Other major contributions:
.\"
.\"  NVRAM detection and reading.
.\"  Copyright (C) 1997 Richard Waltham <dormouse@farsrobt.demon.co.uk>
.\"
.\" ----------------------------------------------------------------------------
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
.\" ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.Dd December 26, 2020
.Dt SYM 4
.Os
.Sh NAME
.Nm sym
.Nd NCR/Symbios/LSI Logic 53C8XX PCI SCSI host adapter driver
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device pci"
.Cd "device scbus"
.Cd "device sym"
.Ed
.Pp
To disable PCI parity checking (needed for broken bridges):
.Cd "options SYM_SETUP_PCI_PARITY=<boolean>"
.Pp
To control driver probing against HVD buses:
.Cd "options SYM_SETUP_SCSI_DIFF=<bit combination>"
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
sym_load="YES"
.Ed
.Sh DESCRIPTION
This driver provides support for the Symbios/LSI Logic 53C8XX
PCI SCSI controllers.
.Pp
Driver features include support for wide SCSI busses and fast10, fast20,
fast40 and fast80-dt synchronous data transfers depending on controller
capabilities.
It also provides generic SCSI features such as tagged command
queueing and auto-request sense.
This driver is configured by default
for a maximum of 446 outstanding commands per bus, 8 LUNs per target
and 64 tagged tasks per LUN.
These numbers are not so much limited by design
as they are considered reasonable values for current SCSI technology.
These values can be increased by changing appropriate
constants in driver header files (not recommended).
.Pp
This driver supports the entire Symbios 53C8XX family of PCI SCSI
controllers.
It also offers the advantage of architectural improvements available
only with newer chips.
.Pp
.Nm
notably handles phase mismatch from SCRIPTS for the 53C896, 53C895A,
and 53C1010 cores.
As a result, it guarantees that no more than 1 interrupt
per IO completion is delivered to the CPU, and that the SCRIPTS processor
is never stalled waiting for CPU attention in normal situations.
.Pp
.Nm
also uses LOAD/STORE SCRIPTS instructions for chips that support it.
Only the early 810, 815 and 825 NCR chips do not support LOAD/STORE.
Use of LOAD/STORE instead of MEMORY MOVE allows SCRIPTS to access IO
registers internal to the chip (no external PCI cycles).
As a result, the driver guarantees that no PCI self-mastering will occur
for chips that support LOAD/STORE.
.Pp
LOAD/STORE instructions are also faster than MEMORY MOVE because
they do not involve the chip DMA FIFO and are coded on 2 DWORDs
instead of 3.
.Pp
For the early NCR 810, 815 and 825 chips, the driver uses a separate
SCRIPTS set that uses MEMORY MOVE instructions for data movements.
This is because LOAD/STORE are not supported by these chips.
.Pp
HVD/LVD capable controllers (895, 895A, 896, and 897) report
the actual bus mode in the STEST4 chip IO registers.
This feature
allows the driver to safely probe against bus mode and to set up the chip
accordingly.
By default the driver only supports HVD for these chips.
For other chips that can support HVD but not LVD, the driver has to probe
implementation dependent registers (GPIO) in order to detect HVD bus mode.
Only HVD implementations that conform with Symbios Logic recommendations can
be detected by the driver.
When the
.Ar SYM_SETUP_SCSI_DIFF
kernel option is assigned
a value of 1, the driver will also probe against HVD for 825a, 875, 876 and
885 chips, assuming Symbios Logic compatible implementation of HVD.
.Pp
When the
.Ar SYM_SETUP_PCI_PARITY
is assigned a value of 0, the
driver will not enable PCI parity checking for 53C8XX devices.
PCI parity
checking should not be an option for PCI SCSI controllers, but some
systems have been reported to fail using 53C8XX chips, due to spurious or
permanent PCI parity errors detected.
This option is supplied for
convenience but it is neither recommended nor supported.
.Pp
This driver offers other options
that are not currently exported to the user.
They are defined and documented in the
.Pa sym_conf.h
driver file.
Changing these options is not recommended unless absolutely necessary.
Some of these
options are planned to be exported through
.Xr sysctl 3
or an equivalent mechanism
in a future driver releases and therefore,
no compatibility is guaranteed.
.Pp
At initialization, the driver tries to detect and read user settings from
controller NVRAM.
The Symbios/Logic NVRAM layout and the Tekram NVRAM
layout are currently supported.
If the reading of the NVRAM succeeds, the
following settings are taken into account and reported to CAM:
.Bl -column "SCSI parity checking" "Symbios"
.It Em "Host settings	Symbios	Tekram"
.It "SCSI parity checking	Y	N"
.It "Host SCSI ident 	Y	Y"
.It "Verbose messages	Y	N"
.It "Scan targets hi-lo	Y	N"
.It "Avoid SCSI bus reset	Y	N"
.El
.Bl -column "Synchronous period" "Symbios"
.It Em "Device settings	Symbios	Tekram"
.It "Synchronous period	Y	Y"
.It "SCSI bus width	Y	Y"
.It "Queue tag enable	Y	Y"
.It "Number of tags	NA	Y"
.It "Disconnect enable	Y	Y"
.It "Scan at boot time	Y	N"
.It "Scan LUN	Y	N"
.El
.Pp
Devices that are configured as disabled for 'scan' in the NVRAM are not
reported to CAM at system start-up.
They can be discovered later using
the
.Ql camcontrol rescan
command.
.Pp
The table below summarizes the main features and capabilities of the
NCR/Symbios/LSI Logic 53C8XX family of PCI SCSI controllers.
.Bl -column sym53c1510d "80MHz" "Width" "SRAM" "PCI64"
.It Em "Chip	Sync	Width	SRAM	PCI64	Supported"
.It "sym53c810	10MHz	8Bit	N	N	Y"
.It "sym53c810a	10MHz	8Bit	N	N	Y"
.It "sym53c815	10MHz	8Bit	N	N	Y"
.It "sym53c825	10MHz	16Bit	N	N	Y"
.It "sym53c825a	10MHz	16Bit	4KB	N	Y"
.It "sym53c860	20MHz	8Bit	N	N	Y"
.It "sym53c875	20MHz	16Bit	4KB	N	Y"
.It "sym53c876	20MHz	16Bit	4KB	N	Y"
.It "sym53c885	20MHz	16Bit	4KB	N	Y"
.It "sym53c895	40MHz	16Bit	4KB	N	Y"
.It "sym53c895A	40MHz	16Bit	8KB	N	Y"
.It "sym53c896	40MHz	16Bit	8KB	Y	Y"
.It "sym53c897	40MHz	16Bit	8KB	Y	Y"
.It "sym53c1510D	40MHz	16Bit	4KB	Y	Y"
.It "sym53c1010	80MHz	16Bit	8KB	Y	Y"
.El
.Sh HARDWARE
The
.Nm
driver provides support for the following Symbios/LSI Logic PCI SCSI
controllers:
.Pp
.Bl -bullet -compact
.It
.Tn 53C810
.It
.Tn 53C810A
.It
.Tn 53C815
.It
.Tn 53C825
.It
.Tn 53C825A
.It
.Tn 53C860
.It
.Tn 53C875
.It
.Tn 53C876
.It
.Tn 53C895
.It
.Tn 53C895A
.It
.Tn 53C896
.It
.Tn 53C897
.It
.Tn 53C1000
.It
.Tn 53C1000R
.It
.Tn 53C1010-33
.It
.Tn 53C1010-66
.It
.Tn 53C1510D
.El
.Pp
The SCSI controllers supported by
.Nm
can be either embedded on a motherboard, or on
one of the following add-on boards:
.Pp
.Bl -bullet -compact
.It
ASUS SC-200, SC-896
.It
Data Technology DTC3130 (all variants)
.It
DawiControl DC2976UW
.It
Diamond FirePort (all)
.It
NCR cards (all)
.It
Symbios cards (all)
.It
Tekram DC390W, 390U, 390F, 390U2B, 390U2W, 390U3D, and 390U3W
.It
Tyan S1365
.El
.Sh MISC
The DEC KZPCA-AA is a rebadged SYM8952U.
.Sh SEE ALSO
.Xr cd 4 ,
.Xr da 4 ,
.Xr sa 4 ,
.Xr scsi 4 ,
.Xr camcontrol 8
.Sh HISTORY
The
.Nm
driver appeared in
.Fx 4.0 .
.Sh AUTHORS
.An -nosplit
The
.Nm
driver was written by
.An Gerard Roudier
and is derived from the
Linux sym53c8xx driver from the same author.
The sym53c8xx driver is derived from the ncr53c8xx driver,
which was ported from the
.Fx
.Xr ncr 4
driver to Linux-1.2.13.
The original
.Xr ncr 4
driver was written for
.Bx 386
and
.Fx
by
.An Wolfgang Stanglmeier
and
.An Stefan Esser .
.Sh BUGS
No known bugs.
